1. Technical Field
The present disclosure relates to devices comprising integrated circuits, and clock interfaces for such devices.
2. Description of Related Art
Integrated circuits often include terminals at which an external clock signal is provided to the device. The external clock signal is delivered to internal circuitry through a clock buffer or other clock circuitry.
The process of implementing a system or device that utilizes integrated circuits often includes connecting the integrated circuits to a bus system or other communication structure that provides the external clock signal. Thus, the nature of the external clock signal that is available for use by the integrated circuit can depend on the system in which it will be utilized. It is not always known in advance what type of system, or what type of external clock, may be available.
In a representative integrated circuit, an external clock provided on a dedicated single clock pin is utilized by single-phase clock circuitry on the device to provide the internal clock used to synchronize the circuitry on the integrated circuit with the external bus system. In another representative integrated circuit that may be configured for higher speed operations, a differential external clock provided on a dedicated pair of clock pins is utilized by clock circuitry on the device to provide the internal clock used to synchronize the circuitry on the integrated circuit with the external bus system. When the bus system implements an external clock in a format that does not match the format for which the integrated circuit is configured, then the integrated circuit can be considered incompatible with that system design.
It is desirable to provide technology to address the compatibility problems that arise in this environment.